Clutch and brake



July 13, 1965 c. E. WINTER CLUTCH AND BRAKE Filed April 1e, 196s FIG.

INVENTOR.

CA L WINTER BY-/JM@ TT/VEYS United States Patent O disastri CLUTCH AND BRAKE Carl E. Winter, 10514 Kiunard Ave., Los Angeles, Calif. Filed Apr. 16, 19163, Ser. No. 273,37l 2 Claims. (Cl. 12-18) This invention relates generally to clutches which may be either manually or electrically controlled and, more particularly, to an improved mechanical clutch apparatus for imparting rotation from an input shaft to an output shaft when in a first clutching position and for either braking or permitting free independent motion of the output shaft when in unclutched position.

Many conventional clutches operate on the simple principle of moving two friction surfaces into clutching engagement with each other to transfer motion from one clutch surface to the other. If a large driving torque is provided on one of the surfaces to rotate the other surface, slippage may result if the turning torque exceeds the friction force as determined by the coefhcient of friction between the engaging surfaces themselves. This coefficient of friction is a function of the normal force pressing the surfaces together. To provide a large normal force requires heavy springs or the like and, as a consequence, it is not always easy to separate the surfaces when it is desired to release the clutch. In other words, to accommodate large torques results in a mechanism in which declutching or separation of the surfaces may require complicated apparatus.

It should also be understood with the foregoing types of clutches that the force normally applied between the surfaces to urge them into pressing engagement is constant. Thus torques only up to a certain limit may be transmitted through the clutch mechanism. It would be desirable if the normal or pressing engagement force between the clutch surfaces could automatically be increased with increasing torque to insure against any slippage between the clutch surfaces.

With all of the foregoing in mind, it is a primary object of this invention to provide an improved clutch apparatus in which extremely large torques may be transmitted ybetween first and second rotating members when the clutch surfaces are in engagement and yet, in which very little energy is required to separate the clutch surfaces.

More particularly, it is an object to provide an improved clutch apparatus in which the normal force pressing two clutch surfaces together is automatically increased with increased torque to the end that extremely large torques may be transmitted without slippage.

Another object is to provide an improved clutch apparatus which may also conveniently include a braking feature to the end that when the clutch surfaces are separated, the driven clutch member may be braked to a stationary position.

lOther objects of this invention are to provide an improved clutch apparatus which may be either manually or electrically operated with very little energy, which is compact in size, extremely reliable in operation and in which the input and output shafts therefor are in axial alignment so that the clutching apparatus may be conveniently inserted in any particular mechanism as a substitute for an elongated shaft between the ends of which a clutch or release function is desired.

Brieiy, these and many other objects and advantages of this invention are attained by providing a casing structure supporting an input rotatable shaft and an output rotatable shaft in axial alignment. The inner end of the output rotatable shaft includes spiral threads upon which is threadedly mounted a clutch collar. This clutch collar includes a clutch surface facing in an axial direction ld? Patented july 13, 1965 towards the inner end of the input shaft. This inner end of the input shaft in turn terminates in an annular clutch member juxtaposed the clutch surface on the clutch collar. The arrangement is such that the clutch collar may be threaded axially along the output shaft towards the clutch member to eifect engagement therewith. Once engagement is achieved, the clutch member on the input shaft will tend to rotate the clutch collar relative to the output shaft resulting in a further threading of the clutch collar in a direction towards the clutch member thereby effecting a tighter engagement between the clutch surfaces.

When further axial movement of the clutch collar is prevented, the clutch collar will b-e locked against rotation to the output shaft so that the output shaft will be forced to turn with the input shaft and the desired clutch action is achieved. Because of the mounting of the clutch collar in a spiral thread on the output shaft, it will be evident that the greater the input turning torque, the greater will be the tendency of the clutch collar to move closer to the clutch member and thus effect a tighter clutching action so that increased torque merely results in an increased pressing engagement and thus substantially no slippage is possible.

When it is desired to release the surfaces, the clutch collar itself need only be retracted or pulled away from the clutch member. Once the clutch surfaces are disengaged, the inertia of the output shaft rotating 4within the clutch collar will result in the threads turning suchas to back off the clutch collar so that once disengagement is achieved, substantially no energy is needed to separate the surfaces.

in accordance with further features of the invention, a lbrake surface may be juxtaposed the opposite end of the clutch collar so that when the clutch collar is backed off, this opposite end will be brought into engagement with the brake surface. As a result, further axial movement of the clutch collar is blocked so that relative rotation between the clutch collar and output shaft is prevented and the output shaft will be braked to a stationary position.

A better understanding of the invention will be had by now referring to a preferred embodiment thereof as illustrated in the accompanying drawings, in which:

FIGURE l is a partial elevational cross-section showing some portions in full lines and some portions cut away of the clutch apparatus when in clutching engagement for transmitting motion between an input and output shaft;

FIGURE 2 is similar to ETGURE l but illustrates the relative positions of movable components in the apparatus when the clutch is out of engagement so that the input shaft may turn independently of the output shaft;

FIGURE 3 is an enlarged fragmentary View of an actuating portion of the clutch apparatus illustrated in FIG- URES 1 and 2; and,

FIGURE 4 is a cross-section taken in the direction of the arrows 4 4 of FiGURE l.

Referring first to FIGURE 1, there is Vshown a casing 1t? having an input shaft Il extending into the left end of the casing and rotatably mounted thereto as by bearings ilZ. An output shaft 13, in turn, extends into the right hand or opposite end of the casing and is rotatably supported by bearings I4. The inner end of the output shaft 1? includes an enlarged diameter portion 15 provided with spiral threads llo. Preferably, the spiral threads i6 are of relatively large pitch and serve to threadedly mount a clutch collar t7.

As shown best in both FIGURES l and 2, the clutch collar i7 includes a rst clutch surface ll annularly extending about the left hand face thereof. This clutch cated' by the cross-sectioning. In' this respect, theclutch member 20, is.` rotatable with the input shaft 11 and includes a'central cutout portion for s-upporting bearings 21 L journaling the end `of the output shaft 13. By this arrangement, the input .and output shafts are held in axial alignment and yet may rotate independently of each other when the clutch surfaces 1S and 19 are out of engagement. VIn a preferred embodiment of the invention, the clutch Y providedI to move the plunger coils`37 are tie-energized Thus, the fingers 28. and 29may i be -moved Yfrom engagement with ',one of the, channel walls collar 17 may also include an, annular clutch surfaceV 22V on its opposite end juxtaposed a brake surface 23 on a stationary brake 24. ,They brake Z4 is secured to the inside of the casing v10 as will be described subsequently.

With the. clutch collar 17 in threaded engagement with the spiral threads 15, it will be clear that threading or rotational movement of the collar 17 about the'enlarged portion will result in axial movement of this clutch collar. It will .also be Vevident that if axial movement of the clutch colla-r 17 isv blocked, the enlarged portion- 15fand shaft 13 will be forced to rotate with the clutch collar if a rotation is imparted thereto.

With the foregoing in mind, it will be evident that if the clutch collar 17 is moved in an axial direction to wards: the `clutch member 20, as soon as engagement be-A tween the clutch surfaces 18 and 19 take place, any rotation of the clutch member 2) will beimparted to the clutch collar 17 and this rotation, if assumed to be in a counterclockwise .direction as'viewed from the -left end :of thein'put shaft 11 in FIGURE 1, will tend to thread the clutch collar 17 further towards the clutch member 20 thereby eiecting a tighter engagement. When` further axial movement of the clutch collar- 17 to the left as viewed in FIGURE l is blocked, the threaded connection. with the enlarged diameter portion 15 of the output shaftA 13 will bind and thusthe output shaft 13 will be caused to rotate with the clutch collar 17.

If now the clutch collar 17 is moved to the right or 4awayrfr-om the clutch member-r2t), and during such move-` ment away from the clutch member 20, vthe clutch collar 17 is slowed or stopped from rotating, the rotational inertia of the output shaft 13 and enlarged diameter porf tion 15 will 'move the spiral threads 16 ina direction such as to aid in moving the'clutch collar 17; to the righrtor 23 and thus prevents further axial movement of the clutch blocked, it is no longer possible for the shaft 23 to rotate,

as a vconsequence of the binding of the threads and thus the loutput shaft 13 will be braked.

In order to eifect the foregoing movement of the clutch member, an ,actuatingV means is provided. In accordance with the .preferred embodiment of the invention, this ac-.

tuating means cooperates with an annular exterior channel 25 -circumscribed .about the clutch collar 17. As shown,IV

this channel includes opposite opposed walls V26 Iand 2,7. The wall-26` is smooth and the Wall V27v is provided with a clutch surface as indicated in FIGURES `1 andZ. The r ,actuating means itself includes ngers 28 and 29 arranged 'Y to be; received in diametricall'y opposite portionsvof fthe :annular channel `25. These fingers are kcarried on the endsV .'50 collar to the right. When this further axial movement :1s

36 to the rightfwhen the to engagement with Athe other by actuation of thesolenoid structureas described.

With particularreference to FIGURE; the nger 28 is .shown in enlarged view whereinit will be noted that v it includes `opposite:surfacesY 4t) and 411er ,respectivevv engagement withthe walls 26 and V27;i'n'Y theV channe1-25 yof the clutch collar 17 As shown, the'wall 40 is smooth,y

whereas the wallf41 is rough to provide aclutch surface.

-FIG-URE4 illustrates the manner; in whichrrthe brake,`

surface 23 is supported. As shown, suitable' struts" or equivalent members 42, 43, t4-and` 45 l'may 4beprovided 'i l to hold the, brake surface `23V in a stationary position to,

the casing. Itiwill also be-evidentfrorn ,FIGURE .4 that the arms 30 .and'31l for-the clutch fingers are rotationally stationary xbutfmay `move :back and forth ;in` adirectiony Y V.of the yario'us com@ g ponents in mind,` the operationffof ther improved clutch apparatus of this-invention willnowgbe described;E `As'Y sume first that the inputshaftll shown inV FIGUREVl is v rotated infa counter-'clockwisedirection as `viewed from the left lookingt-owardsV the casing 10. Assume also that an electrical signal has been Vapplied to th'esolenoid` coils 37 'so that the plunger 36' fismovedxto its eXtreme-left-` ward position( In` this position,fthe ,ar-ms'Stl and 31 willV Y haveV moved Ythe ngers 2S1and V29 so,-.that the ,smooth walledy portions will engage: the smoothwall V`26;V in the annular channel 25 in the clutchc-ojllar 17.' The clutch j collar 17 'willthus be :urged axially 'alongthefenlarged diameter spiral portion lof the; output shaf't1'3'and this axial movement will result in Vrotation ofthe clutch' collar 17@V as 'it threads along-,thislenlarged portion. VWhen fthe clutch collar .surface 18 engagestheclutch membersur:

face V19 asV illustrated in `*FIGURE l, theelutchcollar-l'l i willlbe driven ina counter-clockwise directionV as Viewed from the left'looking towards therightand, as described heretofore, this imparted motion to `the fclutchcollar 17.54

will'tendto further effect; an axial movement towardsthe clutch member, 20 because ofthe direction of the spiral threads 16.I When further axialmovement'of: the clutch', Y

member` 17 is. prevented, the` enlarged diameter(portion 15 andoutputshaft13 willbecaused to rotate'throughfthe Y Imedium ofthe threaded lconnection of theclutch collarlto Y the spiralthreads and thustheshaftsll and 13,.'1Wil1 ro- Y It should be clearly understood thtvery little; energy, is required of the solenoid to move the fingers to drive.y

. the clutch collar 17 ltoward'sthe clutchrmemberfzjand f of arms30 and 31 in turn-connectedV to rods 32 and 33:?

passing throughbores 34 and 35 to a solenoid plunger 36.1'V

shown in the right hand portion :of the casing 10 in both FIGURES 1` and 2. Y W

Cooperating with the 'solenoid plunger 3,6are `solenoid coils 37 'surrounding the plunger .and arranged upon ener- .gization to move the plunger t-o the left or further into,v the center portion of the coils 37. Energization of these coils 37frnay be effected through suitable input leads 3S fromva remote station. VA return solenoid spring 39,-'isy that `once engagement of the clutch'collar 17is madeV with the .clutch member 20, Ythe furtherthreading action as described will move the clutch collar 17;A slightly furthe-r axially in a leftwar-d directionfuntil theychannel surface., 26 is free ofy therendfsurfacey of thengersZSy-Thek plunger 36k is .stopped ,against further leftward 7movement 1 by abutment of the plunger againstthe outlet ofthe boresV 34 .and y35,-'sro`that 4the. fingersV 28 and 29wvill actually be,V out of Contact withlthe'wall surfacef-Z'eterfthe initial,` Y' clutching engagement has. beenYeffectecla Thecflutch collar 17` 'provides its'ownpressi'ng forceV as a consequence: Y Vof ther-thread Vs tructure as described.` Y ,i i It is tozbe understood `accordingly that the clutch col-lar-V Y 17 willrotate with the clutch member 20 Without engagement withany other elementsv and the shaft 1=3 WllalsoV shaft relative Vtto .the'rotation of the, yinput `shaft v111 will simply result inthe spiral grooves lcamming the clutch i collarf17y into closer engagement with the clutch member 20 thereby'jncreasing the Africtional force` between the eni-.

gaging surfaces so that the torque will be accommodated without slippage.

The clutch members will remain in engagement so long as the signal is applied to the coils 37 to hold the plunger 36 in its leftward position against the bias of the spring 39. When it is desired to declutch or separate rotation of the shaft 11 from the output shaft 13, the signal to the coils 37 is terminated so that the spring 39 w-ill then urge the plunger 36 to the right. T his action will result in movement of lthe fingers 28 and 29 to the right through the medium of the supporting arms 3() and 31, to in turn urge the collar 1'7 away from the clutch member 20.

The above situation is depicted in FIGURE 2 where it will be noticed that the clutch surface 41 of the fingers 2S and 29 has engaged the opposite wall surface 27 of the channel 25 so as to slow rotation of the collar 17. When Ithe rotation of .the collar 17 is slowed relative to the rotation of the output shaft 13, the inertia of the rotation of the output shaft 13 will result in the spiral threads rotating relative to the clutch c-ollar tending to threaded-ly back off the collar further in a direction to the right or away from the clutch member 20. Thus, again, very little force is required of the solenoid spring 39 in urging the clutch collar 17 away from the clutch member 20.

In order to brake or stop completely rotation of the output shaft 13, continued movement of the clutch collar 17 to .the right will finally res-ult in its opposite clutch surface 22 engaging the brake surface 23 so that further axial movement of the collar is prevented. The continued inertia of rotation of the output shaft 13, however, will tend to threadedly move the clutch collar 17 into tighter engagement with the brake surface 23 so that immediate braking of the'output shaft 13 will be effect-ed as soon as the collar is prevented from fur-ther axial movement to .the right by the brake surface.

Accordingly, when the components assume the positions illustrated in FIGURE 2, the input shaft 11 is free to rotate independently of the output shaft 13 and the output shaft 13 is held stationary.

If it is Vaga-in desired to couple the input shaft to the out put shaft, the solenoid is simply energized and the fingers 28 and 29 will operate to move the collar towards the clutch member and the sequence of clutching operations will be repeated.

From the foregoing description, it will thus be evident that the present invention has provided a greatly improved clutch apparatus. Not only is the device compact and rugged in design having an input and output shaft in axial alignment, but the more important feature of being able to transmit large torques by providing a clutch engagement force dependent upon the torque in question enables a very positive and reliable clutching action to be realized. Moreover, as a consequence, of this clutching arrangement, very little energy is required to actuate the clutch into clutching engagement or release the clutch from clutching engagement.

While only one preferred embodiment of the invention has been shown and described, various changes and modications that fall clear-ly within the scope and spirit of 6 the invention will occur to those skilled in the art. The clutch apparatus is therefore not to be thought of as limited to the one embodiment set forth merely for illustrative purposes.

What is claimed is:

1. A clutch apparatus comprising, in combination: a casing; yan input shaft extending into one end of said casing; an output shaft in axial alignment with said input shaft extending from the opposite end of said casing, said output shaft terminating within said casing in an enlarged diameter portion having spiral threads thereon; a clutch collar threaded to said enlarged diameter portion and including a first clutch surface facing in an axial direction towards said input shaft, said input shaft terminating in said casing in an annular clutch member having a second clutch surface juxtaposed said first clutch surface, said clutch col-lar including an annular channel circumscribed about its mid-portion and having opposed walls; finger means receivable in said channel; solenoid means for moving said finger means against one of said walls to urge said clutch collar into engagement with said clutch member upon energization of said solenoid means; spring means for moving said finger means against the opposite of said one of said walls to move said clutch collar out of engagement with said clutch member, the direction of said spiral threads being such that rotation of said input shaft tends to thread said clutch collar in a direction into tighter engagement with said clutch member when in clutching engagement therewith; and a brake surface secured within said casing in a position to engage the opposite end of said clutch collar when said clutch collar is moved away from said clutch member whereby said output shaft is braked against rotation by said brake surface through the medium of said clutch collar and said spiral threads.

2. A clutch apparatus according to claim 1, in which the engaging surfaces of said linger means and one wall are smooth so that slipping therebetween can take place with a minimum of friction, and in which the engaging surfaces of said finger means and opposite wall are rough to provide clutch surfaces so that rotation of said clutch collar is initially braked by said finger means when said clutch collar is moved away from said clutch member and towards said brake surface.

References Cited by the Examiner UNITED STATES PATENTS Re. 21,017 2/39 Mellon 192-18 XR 774,850 ll/04 fayer 192-16 1,480,239 1/24 Chaplin 192-35 1,930,290 10/33 Stresau 192-12 XR 1,978,975 10/34 Winans 192-35 2,976,974 3/61 Blyth 192-54 XR 3,049,209 8/62 Reece 192-35 XR FOREIGN PATENTS 525,481 8/ 40 Great Britain.

DAVID J. WILLAMOWSKY, Primary Examiner. 

1. A CLUTCH APPARATUS COMPRISING, IN COMBINATION: A CASING; AN INPUT SHAFT EXTENDING INTO ONE END OF SAID CASING; AN OUTPUT SHAFT IN AXIAL ALIGNMENT WITH SAID INPUT SHAFT EXTENDING FROM THE OPPOSITE END OF SAID CASING, SAID OUTPUT SHAFT TERMINATING WITHIN SAID CASING IN AN ENLARGED DIAMETER PORTION HAVING SPIRAL THREADS THEREON; A CLUTCH COLLAR THREADED TO SAID ENLARGED DIAMETER PORTION AND INCLUDING A FIRST CLUTCH SURFACE FACING IN AN AXIAL DIRECTION TOWARDS SAID INPUT SHAFT, SAID INPUT SHAFT TERMINATING IN SAID CASING IN AN ANNULAR CLUTCH MEMBER HAVING A SECOND CLUTCH SURFACE JUXTAPOSED SAID FIRST CLUTCH SURFACE, SAID CLUTCH COLLAR INCLUDING AN ANNULAR CHANNEL CIRCUMSCRIBED ABOUT ITS MID-PORTION AND HAVING OPPOSED WALLS; FINGER MEANS RECEIVABLE IN SAID CHANNELF SOLENOID MEANS FOR MOVING SAID FINGER MEANS AGAINST ONE OF SAID WALLS TO URGE SAID CLUTCH COLLAR INTO ENGAGEMENT WITH SAID CLUTCH MEM- 